-- @owner: @li-xin12345
-- @date: 2023/8/3
-- @testpoint: LIST分区表，非压缩表改为压缩表
-- @history: Modified by li-xin12345 2025.3.24：研发代码变更，压缩率变化

--step1:建HASH分区表并插入数据;expect:成功
drop table if exists t_alter_rowcompress_0021 cascade;
create table t_alter_rowcompress_0021 (col1 int, col2 int)
partition by hash(col1)
(
partition p1,
partition p2
);

insert into t_alter_rowcompress_0021 values(1, generate_series(0, 500));
insert into t_alter_rowcompress_0021 values(2, generate_series(0, 500));
insert into t_alter_rowcompress_0021 values(3, generate_series(0, 500));
insert into t_alter_rowcompress_0021 values(4, generate_series(0, 500));

--step2:查看表文件占用磁盘大小;expect:成功
select pg_size_pretty(pg_total_relation_size('t_alter_rowcompress_0021')) as table_size;

--step3:数据校验;expect:成功
select checksum(t_alter_rowcompress_0021::text) from t_alter_rowcompress_0021;

--step4:修改表为压缩表，checkpoint;expect:成功
alter table t_alter_rowcompress_0021 set (compresstype = 2);
checkpoint;

--step5:再次查看表文件占用磁盘大小;expect:表文件磁盘占用小于非压缩表
select pg_size_pretty(pg_total_relation_size('t_alter_rowcompress_0021')) as table_size;
select checksum(t_alter_rowcompress_0021::text) from t_alter_rowcompress_0021;

--step6:数据校验;expect:与非压缩表一致
select checksum(t_alter_rowcompress_0021::text) from t_alter_rowcompress_0021;

--step7:查看压缩率;expect:成功
drop function if exists compress_func_findpath(character varying);
create or replace function compress_func_findpath(character varying)
returns character varying
language plpgsql
as
$body$
declare
relpath character varying;
begin
relpath = (select pg_relation_filepath(relname::regclass) from pg_class where relname = $1);
return relpath;
end;
$body$;
/

select is_compress, file_count, logic_size, physic_size, compress_ratio from pg_catalog.compress_ratio_info(compress_func_findpath('t_alter_rowcompress_0021'));

--step8:查看分区表信息;expect:成功，显示压缩参数，只改分区表
select relname, reloptions from pg_partition where relname like '%rowcompress_0018%' order by relname;

--step9:清理环境;expect:成功
drop table if exists t_alter_rowcompress_0021;
drop function if exists compress_func_findpath(character varying);